Diane Sawyer's debut as anchor of ABC's "World News" gave the show a ratings boost. Nearly 9 million viewers tuned in on Monday to see Sawyer's first appearance — up from an average Monday audience of about 8.4 million. But critics disagree on whether Sawyer, who was popular as host of Good Morning America, will go over well with the show's core audience, and whether she's capable of bringing in new viewers. So what are the early indications? (Watch segments from Diane Sawyer's first "World News" show)

Sawyer brings new energy to ABC: Diane Sawyer's signals that "alpha news anchors" are back, says Alessandra Stanley in The New York Times. Her predecessor, Charlie Gibson, was "unpretentious" and easy going. Sawyer's debut was notable for her "utter seriousness," and her Day 1 interview with Iranian President Mahmoud Ahmadinejad showed that behind Sawyer's "twinkly warmth" is enough "high-octane drive" for big stories to match CBS' Katie Couric and NBC's Brian Williams."Sawyer sets her tone as ABC’s anchor"

Her debut was heavy on fluff: Sawyer seemed more "featurey" morning television host that "sober deliverer of the day's news," says Roger Catlin in the Hartford Courant. Yes, she got the interview with Ahmadinejad, but "there was no shortage of fluff, including a ease to the Hollywood death of Britanny Murphy, pictures of Obama visiting a schoolroom and a long pointless report about whether you'll get your gifts mailed on time for Christmas (maybe)." "Diane Sawyer's first night"

A bumpy debut, but a good start: There were a few technical glitches in Diane Sawyers' first appearance as anchor, says Tom Shales in The Washington Post, and ABC seemed so in love with her "gorgeousness" that it kept cameras locked in close ups for most of the show. Sawyer kept referring to viewers as "you" — an old trick to draw people in, but not "very becoming on a truly serious newscast." But Sawyer's experience and "ineffable charm" carried her through, and once she gets the bugs out ABC may have "the best-anchored newscast on television, anywhere.""A few bumps, but Diane Sawyer has solid debut as ABC 'World News' anchor"